C语言实现一个简单的单向链表list

C语言实现一个简单的单向链表list2010-04-30 csdn 张亮用C语言实现一个简单实用的单向链表list，具有一定的实际意义。尤其我们不想使用STL里面的list<...>类的时候。我实现的这个list，结点存储任何调用者分配的任意类型的数据（void*）。这个list适用于一些简单的场合，消耗极少的资源。

头文件：

/*
 * list.h
 *        Generic sequential linked list node structure -- can hold any type data.
 *        cheungmine
 *      Sep. 22, 2007.  All rights reserved.
 */
#ifndef LIST_H_INCLUDED
#define LIST_H_INCLUDED

#include "unistd.h"

typedef struct _listnode_t
{
    struct _listnode_t    *next;
    union{
        void*            data;
        struct _list_t    *list;
        const char        *str;
        long            key;
    };
}listnode_t;

typedef struct _list_t
{
    size_t        size; /* count of nodes */
    listnode_t    *head;
    listnode_t  *tail;
}list_t, *list_p;

/* A prototype of callbacked function called by list_destroy（）, NULL for no use. */
typedef void（*pfcb_list_node_free）（listnode_t* node）;

/* An example of free node data function implemented by callee:
void my_list_node_free（listnode_t *node）
{
    free（node->data）;
}
*/

/* Appends a node to a list */
extern void
list_append_node（list_t *in_list, listnode_t *in_node）;

/* Removes the first node from a list and returns it */
extern listnode_t*
list_remove_head（list_t *in_list）;

/* Removes all nodes but for list itself */
extern void
list_remove_all（list_t *in_list, pfcb_list_node_free pfunc /* NULL for no use or a key node */）;

/* Returns a copy of a list_t from heap */
extern list_t*
list_copy（list_t in_list）;

/* Concatenates two lists into first list. NOT freeing the second */
extern void
list_concat（list_t *first, list_t *second）;

/* Allocates a new listnode_t from heap. NO memory allocated for input node_data */
extern listnode_t*
list_node_create（void* node_data）;

/* Allocates a new listnode_t with a key node type */
extern listnode_t*
list_key_create（long node_key）;

/* Allocates a empty list_t from heap */
extern list_t*
list_create（）;

/* Frees in_list"s all nodes and destroys in_list from heap.
 * the callee is responsible for freeing node data.
 * the node freed-function（pfunc） is called by list_destroy.
 */
extern void
list_destroy（list_t *in_list, pfcb_list_node_free pfunc /* NULL for no use or a key node */）;

/* Gets count of nodes in the list */
extern size_t
list_size（const list_t* in_list）;

/* Gets node by index 0-based. 0 is head */
extern listnode_t*
list_node_at（const list_t* in_list, int index）;


#endif  /* LIST_H_INCLUDED */